In general, a totally automatic washing machine refers to a washing machine that can perform multiple operations including, but not limited to: supplying wash water, washing, rinsing, spin-drying, and draining water. These operations are automatically performed in a single apparatus. Laundry can be washed by wash water flowing past/through the laundry, the impact of wash water on the laundry, and the like.
Various types of totally automatic washing machines include, in general, a main body, a water storage tub, a washing tub, a pulsator or agitator, a pulsator or agitator shaft, a washing tub shaft, a clutch assembly, a motor, and other elements. In such washing machines, the pulsator or agitator is connected to the pulsator or agitator shaft, and the washing tub is connected to the washing tub shaft.
In Korean Patent Application Laid-Open No. 2012-73569, Korean Patent No. 10-1015241, a connection to the pulsator shaft and a connection to the washing tub shaft are selectively and intermittently operated through the clutch assembly.
Particularly, in contemporary washing machines, the clutch assembly and a drain valve are simultaneously and intermittently operated by the motor.
For example, as illustrated in FIGS. 1 and 2, one side (110 of FIG. 3) of a link lever 100 is connected to a drain valve (not illustrated) in a drain assembly 10 to intermittently drain wash water through an inlet 11, and the other side (120 of FIG. 3) of the link lever 100 is connected to a clutch lever 21 to finally and intermittently operate a clutch assembly.
In the clutch assembly, the clutch lever 21 is connected to a lift lever 22, and the lift lever 22 is connected to a coupling 23. Rotor teeth 24 are disposed at an upper portion of the coupling 23, and fixed base teeth 25 are disposed at a lower portion of the coupling 23.
The rotor teeth 24 are connected to a washing tub shaft 30, and the coupling 23 is connected to a pulsator shaft 40. The pulsator shaft 40 is rotatably coupled to a hollow portion (an opening) in the center of the set of rotor teeth 24.
As illustrated in FIG. 1, the drain valve is closed when the link lever 100 is pulled, e.g., during washing; and as illustrated in FIG. 2, the drain valve is opened when the link lever 100 is released (no longer pulled), e.g., during spin-drying. In an alternative implementation, the drain valve is opened when the link lever 100 is pulled (e.g., during spin-drying), and closed when the link lever is released (e.g., during washing).
As illustrated in FIG. 1, during washing, the coupling 23 is raised and engaged with the rotor teeth 24. As a result, because the lower portion of the pulsator shaft 40 is coupled to the coupling 23 like a spline, the washing tub shaft 30 and the pulsator shaft 40 rotate together.
In contrast, as illustrated in FIG. 2, during spin-drying, the coupling 23 is lowered, releasing the engagement between the coupling 23 and the rotor teeth 24. Instead, the coupling 23 is engaged with the base teeth 25 that are disposed at the lower portion of the coupling 23. As a result, only the washing tub shaft 30 rotates (the pulsator shaft 40 does not rotate together with the washing tub shaft 30).
However, the aforementioned washing operation and spin-drying operation are merely examples. In some types of washing machines, during washing, only the pulsator or agitator is rotated, only the washing tub is rotated, and/or the pulsator and the washing tub are simultaneously rotated.
During spin-drying, both the washing tub and the pulsator or agitator may be rotated. However, in some types of washing machines, during spin-drying, only the washing tub is rotated, and/or the pulsator or agitator is maintained in a free state so as to prevent laundry from being damaged due to a collision between the laundry and the pulsator or agitator.
As illustrated in the examples of FIGS. 1 and 2, when the link lever 100 is pulled, the coupling 23 is raised upward and can engage with the rotor teeth 24; and when the link lever 100 is released, the coupling 23 is lowered and the engagement between the coupling 23 and the rotor teeth 24 is released, allowing the coupling 23 to engage with the base teeth 25.
However, as illustrated in FIGS. 1 and 2, with reference also to FIG. 3, one side (portion 120) of the link lever 100 is securely coupled to the clutch lever 21. Therefore, there may be a problem when the coupling 23 is lowered because it may not separate completely from the rotor teeth 24 due to the force with which it is engaged with the rotor teeth 24 and/or because the link lever 100 is connected to the drain valve by a spring that may not be fully operational.
On the other hand, when the coupling 23 is raised, there may be a problem because it may not separate completely from the base teeth 25, because of the force with which it is engaged with the base teeth 25. This can be particularly problematic when the laundry presses up against the pulsator shaft 40 (that is, when the weight of the laundry is applied to the pulsator shaft 40).
The washing machine may not operate smoothly because of the aforementioned problems. Furthermore, if spin-drying starts before the coupling 23 moves from its position for washing (the raised position) to its position for spin-drying (the lowered position), then the coupling 23 may be engaged with the base teeth 25 by only the slight amount of force present when spin-drying starts.
Consequently, because the motor may be already rotating at a high speed when the coupling 23 and the base teeth 25 engage each other, the coupling 23 can be abraded or damaged from impacting the base teeth. A similar problem can occur when the coupling 23 is moved from its position for spin-drying to its position for washing.